Nondiffusing metallic salt coupler compound



l 1942- w.b. PETERSON 2,

- NONDIFFUSING METALLIC SALT COUPLER COMPOUNDS;

' Filed Sept. 29, 1939 Fig 1 l N SILVER HALIDE LAYER CONTAINING'THESILVER 5m m OFA HETEROCYCUC-RING-CONTA|NIHG COUPLER SUPPORT Fig.2;

BLUE SENSITIVE}LAYERS conmume SILVER BEEN SENSITIVE SALT OFAHETEROCYCLIC- mmmwmvm;

- RED SENSITIVE RING- CONTAINING COUPLER SUPPORT Patented Sept. 22, 1942COBIPO UND Willard 1). Peterson, Rochester, N. Y., assignor to EastmanKodak Company, Rochester, N. Y., a corporation of New Jersey ApplicationSeptember 29, 1939, Serial No. 297,153 In Great Britain October 26, 19385 Claims.

This invention relates to photographic color forming or couplingcompounds and particularly to coupler compounds which are non-diffusingwhen incorporated in sensitive emulsion layers.

The product of photographic images by means 01. a coupling reactionbetween a photographic developer and an intermediate or couplingcompound upon which photographic development is well known, having beendescribed in Fischer;

U. S. Patent 1,055,155 and numerous patents 0 which have issued morerecently. One method of carrying out a color forming of this type is toincorporate the coupling compound in the sensitive emulsion layer priorto coating it on the support. When the coupling compound is incorporatedin the sensitive layer in this way, a number of requirements must bemet. Probably the most important of these is that the coupling compoundmust not wander or. diffuse from the layer in which it is incorporated.This is especially important when two or more layers are superposed andare differentially sensitive, as obviously the. wandering of a couplingcomponent would cause inaccurate color rendition. Another requirement isthat the coupling compound, when incorporated in the sensitive layer,should not desensitize or otherwise adversely affect the emulsion layer.7 I I I have found that these requirements for coupling components maybe attained by the use of derivatives of well known coupling compoundswith certain heterocyclic compounds containing active groups in which ametal atom may be substituted to render the compound as a wholenondifiusing.

the coupling compounds are characterized by the fact that they containan imino (NH) group in .the nucleus. These heterocyclic nuclei may alsocontain an SH group in the nucleus and the hydrogen atom of either theNH or the SH group may be replaced by a metallic atom such as a silveratom.

In the accompanying drawing, Fig. 1 is an enlarged sectional view of asingle-layer element, and Fig. 2 is an enlarge'd sectional view of athree-layer element containing in the emulsion layers the silver salt ofa heterocyclic-ring containing coupler.

The heterocyciic nuclei suitable for incorporating into couplercompounds according to my invention are characterized by the fact thatthe imino group which they contain is not more than two atoms distantfrom an atom which has an unshared pair 01' electrons. The atom whichhas the unshared pair of electrons may be, for

example, a nitrogen atom or a sulfur atom and may be in the heterocyclicring or attached to an atom which is a member of the ring. It is a wellknown principle of chemistry that nitrogen v 85 The heterocycliccompounds which react with may exist with valences of either three orfive and that sulfur may exist with valences of two, four or six. Whennitrogen has a valence of three, it has therefore an unshared pair ofelectrons and when sulfur has a valence of two, it has one or twounshared pairs of electrons.

The following are suitable heterocyclic compounds into which couplinggroups may be introduced to form compounds capable of being rentierednon-diffusing according to my invention. i

1, 2, 3-triazo1e N-CH N 11 -NH 1, 2, i-triazole Indawle NIL-N2-mercapto-5-aminothiobiazole 5. Bic-NH =s O: I IH Thiohydantoin I 6.HaC-NH O-BH HaC-N Ethylenethiourea Mereapto benzlmidazolc 8. HNC=OThiobarbituric acid HN-C Thiourazole Dihydro quinazolino 5, iii/EPerimidino HC-N Imldawlo Tetrazolo Tetrazolono Thioisatin HaG-CH:

1,2,3-triazolin Pyrazole anthrone troduced into the heterocyclic nucleiI do not mean that the final compound is necessarily formed by simplesubstitution starting with these two materials. The final compound maybe formed by any suitable reaction which results in a compound having aheterocyclic portion as described above and a coupler portion orportions containing at least one group capable of reacting to form a,dye image.

The functional or reactive group common to the coupler compounds whichreact with primary aromatic amino developing agents to forma coloredimage is a reactive methylene or reactive ethanol group and this groupmay occur at various positions or more than a single position in thecoupler molecule. By reactive methylene, I means a CH2 group which isreactive in the coupling process. The CH2 group usually is presentbetween two negative centers as, for example, in the groups -COCH2-CO-,

. in many cases, be substituted without destroy- Cil ing chemicalactivity of the group. By reactive ethanol, I mean the group This groupoccurs in the phenolic and naphtholic coupler compounds which arereactive in the ortho or para position with respect to the position ofthe hydroxyl group.

The reactive NH or SH group of the heterocyclic systems herein disclosedreacts with metal salts to permit the formation of an insoluble saltsuch as a silver, gold, nickel, mercury or tin salt. Silver salts arepreferred since a silver salt is ordinarily used in the product oisensitive photographic layers and common silver salts such as silverchloride or silver bromide are suitable for the purpose of my invention.Other silver salts which may be used are silver ferricyanide, silverorthophosphate, silver arsenate, silver oxalate, silver cyanate, andsilver citrate.

The reaction of the metal salts with the herein described heterocyclicsystem of the coupling compounds is ionic and rapid and involves asimple replacement of the hydrogen atom of the NH or SH group by themetal atom of the metallic salt employed.

The non-diffusing metal salts made according to my invention may beincorporated in single gelatin layers or layers of other colloidalmaterials such as cellulose esters or natural or synthetic resins.Non-diffusing silver salts according to my invention may also beincorporated in gelatino-silver halide emulsions intended for coating assuperposed layers to form multi-color photographic elements.

The following example, which is illustrative only, indicates a, methodof forming a multi-layer photographic element according to my invention.The coupler compound S-(ortho-hydroxybenzoylamin0)-indazole having thefollowing formula:

and excess silver nitrate. H graphic emulsion which contains sensitivesilver halide and silver salt of the coupler is coated on is dissolvedin methyl alcohol in the amount of 2.5 grams in 40 cc. of methyl alcoholcontaining 0.8 gram of sodium hydroxide. This solution is added to oneliter of 10% gelatin solution which is stirred vigorously while thetemperature 'is maintained at 38-44" C. To this solution are added 150cc. of l-N-silver nitrate with stirring. After a few minutes, 140 cc. ofl-N potassium bromide solution are added slowly to the gelatin solutioncontaining the silver salt of the coupler a support in the usual way.The coupler is retained in its respective layer by virtue of itsinsoluble salt generated by replacement of the imino' hydrogen atom ofthe indazole nucleus.

A second emulsion is produced in the same way using the coupler 5-(2-cyanoacetyl-5-sulfon-' the following formula:

x in the amount of 2.5-grams, using with'this 150 cc. of l-Nsilvernitrate solution and 142: cc. of l-N potassium bromide solution. Theemulsion The resulting ph'otoformed in this way is coated over the firstemulsion layer.

A third emulsion is formed according to the same method using 2.8 gramsof the coupler 5- benzoyl' acetaminobenzutriazole which has the formula:

with which is used 150 cc. of 1-N silver nitrate solution and 140 cc. ofl-N potassium bromide solution. This emulsion is coated on the secondemulsion with a yellow filter layer in gelatin between the second andthird emulsion layers. The yellow filter may consist of any suitablematerial such as colloidal silver in gelatin. The yellow filter is usedfor the purpose of preventing the action of blue light on the first andsecond coated emulsion layers.

The emulsion layers coated in this way produce respectively cyan,magenta and yellow images upon development with a p-phenylene diaminedeveloping agent containing a primary amino group. The element may beexposed and devel-- oped directly to forms. negative color image or apositive image may be obtained by first developing in an ordinary blackand white developer followed by color development of the remainingsilver halide.

My invention will now be described with particular reference to theaccompanying drawing. As shown in Fig. 1, it is a support of anysuitable material such as cellulose nitrate, cellulose acetate, or othercellulose ester, paper, or other opaque material. On the support ill iscoated the emulsion layer II which is a silver halide layer containingthe silver salt of a heterocyclic-ringcontaining coupler according to myinvention. Fig. 2 is a multi-layer element in which the support In iscoated with layers l2, I3, and I4 sensitive, respectively, to the red,green, and blue regions of the spectrum. These layers each contain thesilver salt of a heterocyclic-ring-containingcoupler, the couplerportion of which ordinarily is chosen so that it produces a dye ondevelopment which is complementary in color to the original sensitivityof the layer. It is to be understood that an element of this type maycontain filter, subbing, antl-haltion, or other layers commonly used insuch materials.

A developer suitable for either negative or posi tive development incolors of the elements described above is as follows:

Potassium bromide grams 2.5 Sodium sulfite do 05 Sodium carbonate"do---" 60 p-Aminodiethylaniline hydrochloride do 2.5 Water to liter 1Development is preferably carried out for about ten minutes at 65 F.after which the element is treated with a ferricyanide and hypo bath toremove the silver and any undeveloped silver halide which the filmcontains. This bath may also re-" move any unused coupler in the layeralthough it is immaterial whether or not the unused coupler is removed.

My invention is capable of numerous variations and it isto be understoodthat it is to be considered as limited only by the scope of the appendedclaims.

What I claim is:

1. The method of producing a color-forming photographic emulsion whichcomprises incor porating in a colloidal material a coupler compoundcontaining a heterocyclic nucleus having therein an imino group thehydrogen of which is replaceable by a metal atom to render the compoundmon-diffusing, the lmino group being not more than two atoms distantfrom an atom which has an unshared pair of electrons, then treating thecolloidal material with a metal salt more soluble than the metal salt ofthe coupler to replace the hydrogen atom of the imino group, and forminga sensitive silver salt in the colloidal material.

.2. The method of producing a color-forming photographic emulsion whichcomprises incorporating ingelatin a coupler compound containing aheterocyclic nucleus having therein an imino group the hydrogen of whichis replaceable by silver to render the compound non-diffusing, the

- iriiino group being not more than two atoms distant from an atomselected from the group consisting of sulfur and nitrogen, which has anun shared pair of electrons, then treating the gelatin with a silversalt more soluble than the silver salt of the coupler to replace thehydrogen atom of the imino group, and forming a sensitive silver salt inthe gelatin. r

3. The method of producing a color-forming photographic emulsion whichcomprises incorporating in gelatin a coupler compound containing abenzotriazole nucleus having therein an imino group the hydrogen ofwhich is replaceable by silver to render the cbrnpound non-diffusing,the imino group being not more than two atoms dis tant from the nitrogenatom of the benzotriazole nucleus, which has an unshared pair ofelectrons, then treating the gelatin with a silver salt more solublethan the silver salt of the coupler to replace the hydrogen atom of theimino group, and

. forming a sensitive silver salt in the gelatin.

ing an lndazole nucleus having therein an imino group the hydrogen ofwhich is replaceable by silver to render the-compound non-diffusing, theimino group being not more than two atoms distant from the nitrogen atomof the indazole nucleus, which has an unshared pair of electrons, thentreating the gelatin with a silver salt more soluble than the silversalt of the coupler to replace the hydrogen atom of the imino group, andforming a sensitive silver salt in the gelatin.

5. The method of producing a colored photographic image in agelatino-silver halide emulsion layer which comprises coupling thedevelopment product of an aromatic amino developing agent containing aprimary aromatic amino group in a gelatino-silver halide emulsion layerwith a non-diffusing coupler compound contained in said layer,comprising a silver salt of a heterocyclic nucleus containing areplaceable hydrogen atom on a negative atom not more than two atomsdistant from an atom which has an unshared pair of electrons saidcoupler compound containing at least one group selected from the classconsisting of methylene and ethenol which is reactive with thedevelopment product of aromatic amino photographic developers.

WILLARD D. PETERSON.

